How to retain MDF and LDF disk sizes for one year on Spotlight Statistics Repository database? (147737)

Title

How to retain MDF and LDF disk sizes for one year on Spotlight Statistics Repository database?

Description

User needs to retain MDF and LDF disk sizes of databases for one year. User also needs to retain data and log space used in databases. How to configure Spotlight Statistics Repository to retain this data for one year? They need this to create trending reports. Also, is it possible to import older data on disk sizes?